Studies have been conducted on the identification of modal parameters including natural frequencies, damping coefficients and mode shapes of the Nottingham Wilford Bridge using ambient excitation. An approach to estimate modal parameters, from only output data (in the time domain) using the wavelet transform, is presented. Displacements responses of this structural system are used in the wavelet transform to identify its dynamic characteristics. To measure real-time displacement of the bridge a global positioning system (GPS) sensor network was designed and installed on the bridge. The modal properties were extracted using a two-step methodology. In the first step, the random decrement method was used to transform random signals in free vibration responses. Finally, the Eigensystem Realization Algorithm and a Wavelets based technique were used to extract natural frequencies and to determine the mode shapes of the structure.
- Suspension bridge
- Deflection Monitoring